Matthew 13:10
And the disciples came and said to him, Why dost thou speak to them in parables?
Mark 4:10
And when he was in private, they who were about him, with the twelve, asked him about the parables.
Mark 4:33-34
And with many such parables he spoke the word to them, as they were able to hear.
Treasury of Scripture Knowledge
Summary
And the disciples came, and said unto him, Why speakest thou unto them in parables?